An air-source heat pump optimized for cold climates reduced the energy used for heating military barracks by nearly 20 percent during an ESTCP demonstration at Camp Atterbury, a National Guard base in southern Indiana. Further commercialization efforts are now under way with a national HVAC manufacturer based on the success of this demonstration.
This successful demonstration will help the Department of Defense (DoD) expand the use of air-source heat pumps to the northern half of the United States. Cold Climate Heat Pumps (CCHPs) are less expensive to operate than an electric furnace and are cost competitive with fossil fuel combustion sources of heat. The technology also has the potential for reducing greenhouse gas emissions because the pumps are powered by electricity that could come from renewable sources.
A joint university and industry team—Purdue University, Trane, Emerson Climate Technologies, Danfoss, and Automated Logic Corporation of Indiana—collaborated on the design and field demonstration of the heat pump. The testing was conducted in barracks buildings typical of the small- to medium-sized buildings encountered on military bases. Each building was approximately 6,000 ft2 and constructed of cinderblocks. The barracks were roughly 50 years old but had recently been updated with insulation, a sheet metal roof, and a new central HVAC system. Both buildings had two zones using separate heating and cooling equipment, which allowed for a direct comparison of the CCHP technology to the original HVAC system that used a gas furnace.
Field measurements from this first full-scale field demonstration of the CCHP technology showed a 19% reduction in energy use and carbon dioxide (CO2) emissions, but no savings in operating costs due to the currently low price of natural gas. Performance objectives for comfort, ease of installation, and maintenance were met.
The field demonstration success has led to a new partnership with Unico, Inc. of St. Louis, Missouri, to move the CCHP technology toward full-scale commercialization. Further improvements in CCHP performance are anticipated. Implemented in small commercial or residential buildings in cold climates, CCHPs can help DoD meet its goals to reduce energy use.